Alexander l



UNITED STATES PATENT OFFICE.

ALEXANDER L. SCOTT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF PART TOHIMSELF, WILLIAM H.

BAKER, OF SAME PLACE.

ADDIOKS, AND \VILLIAM HOWARD SPECIFICATION forming part of LettersPatent No. 262,133, dated August 1, 1882.

Application filed May 15, 188:2. No specimens.)

To all whom it may concern:

Be it known that; I, ALEXANDER L. SCOTT, ot' the city and county ofPhiladelphia and State of Pennsylvania, have invented a new and usefulcomposition of matter, consisting of an artificial conglomerate-rockcompound capable of being formed while in a plastic stateinto'paving-blocks, building-bricks, or smooth road'surfaces, or thelike structures, of which the following is a specification.

My invention has for its object the production of an artificialconglomerate rock or stone compound which, after being molded intoblocks or bricks or laid as a surface covering, shall be capable ofresisting disintegrating influences of heat and moisture and the wearand tear of the travel and pressure to which it may be subjected in itsseveral uses.

It consists of a composition of matter of the following ingredients,combined in the proportions named, to wit: three and one-half per cent.of native Trinidad asphaltum, two and one-half per centof coal-tarpitch, one per cent. of crude asbestus, one per cent. of oxide of lead,one per cent. of crude commercial litharge oralum,sixteen percent. ofrefuse foundrysand or its equivalent, and seven ty-five per cent. ofbroken granite or other similar rock of a hard fiinty nature, onethirdof said rock being reduced to grains and two-thirds thereof being brokeninto various small sizes, as may be 'required.

In manufacturing or compounding the elements of my compound 1 followsubstantially this process: I first place the three and onehalf percent.0f native Trinidad asphaltum in a jacketed reducing-kettle heatedto asuflicient temperature by superheated steam introduced into thesteam-jacket at a point at or near the bottom of the kettle, and, by theheat so applied reduce the asphaltum to a fluid state. I also place in aseparate jacketed kettle of similar construction, heated in like manner,the two and one-half per cent. of coal-tar pitch, which I also raise toa sufficient temperature to reduce it to a fluid state. I then removethe liquid asphaltum and pitch from the reducingkcttles and place themtogether in a horizontal steam-jacketed mixer of suitable construc- 1lion, heated by steam from a superheater. 5.0 I While they are beingtreated in this mixerI add tothe fluid compound oneper cent. of crudeasbestus,one per cent. ot'oxide oflead, and one per cent of crudecommercial litharge or alum, and treat the mass in the mixer until theingredientsarethoroughlyintegrated. Whilethis process is being carriedout I place in another mixer, (for which I prefer a cylindricalconstruction,) which is heated from a fire-box suitably constructedbeneath the same, the sixteen per cent. of refuse foundry-sand, togetherwith the seventy-five per cent. of broken granite or other rock of asimilar hard and flinty nature,

of which one-third has been reduced to apul- "erizcd or sandy conditionand theother twothirds broken to small and suitable sizes. I then heatthis mixture of rock and sand while in the mixer to a temperature notexceeding 200 Fahrenheit, and when sufficientl y treated in the mannerdescribed to drive out moisture and thoroughly mix the materials, thesand and rock, while warm, are removed to a horizontalsteam-mixercontaining the fluid compound of asphaltum, coal-tar pitch,oxide of lead, and litharge or alum, as above described. I then treatthe whole mass in this mixer until it is thoroughly compounded andintegrated, and while in a plastic state it may be removed to be moldedinto forms or laid upon surfaces. \Vheu molded into forms such aspavingblocks or building-bricks, it is placed in suitable molds andformed under sufficient pressure into the shapes desired. \Vhile thecompound is still warm and yet in the molds I remove the moldscontaining the blocks or forms and subject them to a bath of heateddilute sulphuric acid, or heated dilute sulphuric acid in which leatherscraps have been steeped. This bath has the effect of shrinking theblocks or forms so as to permit their removal from 0 the molds withcertainty of retaining perfection of form and outline, and it alsotoughens the material of which the block is compounded, and at the sametime cleanses its surface from all the superfluous oils and othermatters which have been brought to the surfaces during the process ofpressure while in the molds, and serves to give to the surfaces anappearance suitable for immediate use, and to partially or whollyvulcanize the same.

\Vheu it is desired to use this compound to form pavements or surfacesof other than block formation it is taken directly from the mixer whilein a plastic state and placed upon a firm gravel or other foundation ofa sufficient thickness, rolled under sufficient pressure, andimmediately thereafter treated with the acid washing hereinbeforedescribed.

\Vhen the composition is used for the manufacture of bricks or otherbuilding material the color may be controlled by the addition ofsuitable coloring-matters while the compound is passing through thesteam-jacketed mixer.

Having fully described my invention, I claim- 1. As a new composition ofmatter, the artificial conglomerate-rock compound formed of acombination of native Trinidad asphaltum, coal-tar pitch, oxide of lead,asbestus,litharge or alum, refuse foundry-sand or its equivalent. andpulverized and broken granite or rock of a similar fiinty nature, in theproportions and substantially in the manner hercinbefore set forth, andfor the purposes specified.

2. The method hereinbefore described of treating asphaltic, bituminous,or composite blocks or surfaces for paving and other uses by subjectingthe same to a bath or wash of warm dilute sulphuric acid in whichleather scraps have been steeped, immediately after the application ofpressure, substantially as described, and for the purposes specified.

3. The method hereinbefore described of treating asphaltic, bituminous,or composite blocks or surfaces for paving and other uses by subjectingthe same to a bath or wash of warm dilute sulphuric acid immediatelyafter the application of pressure, substantially as described, and forthe purposes specified.

ALEXANDER L. SCOTT.

Witnesses:

S. G. WlLsoN, J. H. DIXON.

